Recently a thread discussed using rubber bands, zip ties or what ever else to tension the MechMate drive motors to the rack. This had me think that "what if it's too tight" ? What if the motors have too much direct tooth pressure and not enough movement within the engagement to "find a comfortable mesh".

I visited a machine locally that had begun to show signs of chatter and restriction of movement on the x/y change during curve and circle cutting. This is usually the sign of the everything beginning to loosen up. A grub screw, a bearing hold-down, a motor pivot shaft - something. This machine was what appeared perfect.

What I found was the machine, over time, actually tightened up some, and was restricting the gentle (built in the design) anti-backlash performance of the machine. What we found was that the too tight spring, the slightly tight adjustment bolt/nut on the swing plate and the slightly to snug motor pivot point caused the machine to make noise, shutter on transition and expose inaccuracies.

Well.... intresting. I have on my MM drive tension springs taken from car drum brake pads. And for installing installing them i need lock pliers and lots of force. And i changed weaker springs for them because of chattering...